What I rely on most - Time afield and patience..
I feel like calling is over rated.. I used to stress about my calling being perfect until I heard enough real hens and realized they sound terrible.. I call soft and scratch in the leaves 98% of the time.. If you are in the right place, it shouldn't take any more than that..
I try and set up to where when I can see the turkey, he is at or around 30yds.. I miss out on the excitement of watching them come from afar, but it cuts down on misses (nightmare fuel).. Also, a well maintained and patterned gun is a priority..
I usually get my calls out a month before season and run through them a time or two and that is it.. As stated before, calling is a tiny fraction of being successful in the turkey woods IMO.. I feel the physical ability to get in a better position in a timely manner is much more important..